Question

Write a chemical equation for the reaction that occurs when PbS is roasted in air. Why might a sulfuric acid plant be located near a plant that roasts sulfide ores?

Short answer

The chemical equation for the roasting of PbS in air is given by: \[2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2\text{SO}_2\]. A sulfuric acid plant may be located near a plant that roasts sulfide ores because the roasting process produces sulfur dioxide (SO2), which can be used as a raw material for sulfuric acid (H2SO4) production. This reduces transportation costs and minimizes potential pollution from sulfur dioxide emissions.

Step-by-step solution

Writing the chemical equation for the roasting of PbS in air

To write the chemical equation for the reaction, we need to combine the reactants (PbS and O2) and the products (PbO and SO2). The balanced chemical equation for the reaction can be written as: \[2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2\text{SO}_2\]

Explaining the significance of the sulfuric acid plant's location

A sulfuric acid plant might be located near a plant that roasts sulfide ores because the roasting process produces sulfur dioxide (SO2) as one of its products. Sulfur dioxide can be used as a raw material in the production of sulfuric acid (H2SO4). The reaction for the formation of sulfuric acid from sulfur dioxide is as follows: \[2 \text{SO}_2 + O_2 + 2 \text{H}_2\text{O} \rightarrow 2 \text{H}_2\text{SO}_4\] By locating the sulfuric acid plant near the plant that roasts sulfide ores, the transportation cost of sulfur dioxide can be minimized, and it can also help in reducing potential pollution or harmful effects associated with the release of sulfur dioxide into the atmosphere.

Key concepts

Roasting Process

In the world of chemical reactions, the roasting process plays a significant role in metal extraction. This process involves heating sulfide ores in the presence of oxygen. The primary goal is to convert the metal sulfide into a metal oxide, while releasing sulfur dioxide (SO2) gas. For instance, the roasting of lead sulfide (PbS) can be represented by a balanced chemical equation:

• \[2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2\text{SO}_2\]

During this process, oxygen from the air combines with lead sulfide to form lead oxide (PbO) and sulfur dioxide. Roasting is a crucial step in metallurgy, preparing metals for further refining or direct use. This is because converting sulfides to oxides helps in later steps like smelting, which can be more straightforward with oxides rather than sulfides."

Sulfur Dioxide

Sulfur dioxide (SO2) is a colorless gas with a sharp smell, commonly produced during ore roasting and combustion of sulfur-containing materials. It's an important intermediate in the industrial world. In the mentioned roasting reaction, sulfur dioxide is generated from the oxidation of sulfur in lead sulfide. SO2 is more than just a byproduct; it plays a vital role in industrial applications. Besides its significant use in producing sulfuric acid, sulfur dioxide also finds roles in:

• Preserving dried fruits by inhibiting microbial growth
• In pulp and paper manufacturing as a bleaching agent
• Aiding in preventing wine oxidation to ensure freshness

However, it is important to control SO2 emissions as it can contribute to environmental pollution leading to acid rain. Hence, industries need to strategize how to utilize or manage SO2 effectively."

Sulfuric Acid Production

Sulfuric acid (H2SO4) is one of the most widely produced chemicals worldwide, with diverse applications. Its production is intrinsically linked to sulfur dioxide (SO2) derived from processes like the roasting of sulfide ores. The conversion of sulfur dioxide into sulfuric acid involves a series of reactions, starting with the oxidation of SO2 to sulfur trioxide (SO3), and further reaction with water to form sulfuric acid:

• \[2 \text{SO}_2 + O_2 \rightarrow 2 \text{SO}_3\]
• \[\text{SO}_3 + \text{H}_2\text{O} \rightarrow \text{H}_2\text{SO}_4\]

The practicality of situating a sulfuric acid plant near a sulfide-roasting plant is evident. Proximity reduces transport costs of sulfur dioxide and lessens environmental impact by minimizing its atmospheric release. Sulfuric acid itself is indispensable, used in:

• Fertilizer manufacturing, notably phosphates
• Petroleum refining
• Cleaning metals, as in pickling baths

Therefore, integrated plant locations optimize resource use and align with sustainable industrial practices."